APES Ch 5 Vocab

Species richness

The number of different species in an area.

Species evenness

How evenly individuals are spread among species.

Phylogeny

The evolutionary history of a species.

Evolution

Changes in populations over generations.

Microevolution

Small changes in genes within a population over time.

Macroevolution

Large evolutionary changes that can lead to new species.

Gene

A section of DNA that controls a trait.

Genotype

The genes an organism has.

Phenotype

The traits an organism shows.

Mutation

A change in DNA.

Recombination

The mixing of genes during reproduction.

Evolution by artificial selection

Humans choose which organisms reproduce for certain traits.

Evolution by natural selection

Organisms with helpful traits survive and reproduce more.

Fitness

How well an organism survives and reproduces.

Adaptation

A trait that helps an organism survive and reproduce.

Gene flow

The movement of genes between populations.

Genetic drift

Random changes in gene frequencies in a population.

Bottleneck effect

A population becomes very small, reducing genetic diversity.

Extinction

When a species dies out completely.

Founder effect

A new population starts with only a few individuals and has less genetic diversity.

Geographic isolation

A physical barrier separates populations.

Allopatric speciation

New species form because populations are geographically separated.

Reproductive isolation

Populations can no longer reproduce successfully with each other.

Sympatric speciation

New species form in the same geographic area.

Genetically modified organism

An organism whose DNA has been changed using genetic engineering.

Range of tolerance

The conditions an organism can survive in.

Fundamental niche

All the conditions and resources a species could use to survive.

Realized niche

The conditions and resources a species actually uses.

Distribution

Where a species lives.

Niche generalist

A species that can live in many conditions and use many resources.

Niche specialist

A species that needs specific conditions or resources.

Mass extinction

When many species become extinct in a relatively short time.